Use an External ResourceDictionary in a WindowsPhone 7 app

Question

I am trying to create an ResourceFile Called DataTemplate.xaml in an external dll and use that in a WP7 page. When I do the following in the header of my Page I get an erro

Answer 1

I tried the pack syntax while trying to share XAML ResourceDictionary files and got the same error message. I ended up using this syntax and it worked for me.